From 3ab26f9f0021dd4d519a0fd1fc976a0c399f8f08 Mon Sep 17 00:00:00 2001
From: Izorkin <izorkin@elven.pw>
Date: Thu, 9 Feb 2023 14:03:54 +0300
Subject: [PATCH] nixos/dhcpcd: add IPv6rs option

---
 .../doc/manual/release-notes/rl-2305.section.md |  1 +
 nixos/modules/services/networking/dhcpcd.nix    | 17 +++++++++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/nixos/doc/manual/release-notes/rl-2305.section.md b/nixos/doc/manual/release-notes/rl-2305.section.md
index e23f1b562e71..f4fdc38493c2 100644
--- a/nixos/doc/manual/release-notes/rl-2305.section.md
+++ b/nixos/doc/manual/release-notes/rl-2305.section.md
@@ -284,6 +284,7 @@ In addition to numerous new and upgraded packages, this release has the followin
   ```
 
 - `services.dhcpcd` service now don't solicit or accept IPv6 Router Advertisements on interfaces that use static IPv6 addresses.
+  If network uses both IPv6 Unique local addresses (ULA) and global IPv6 address auto-configuration with SLAAC, must add the parameter `networking.dhcpcd.IPv6rs = true;`.
 
 - The module `services.headscale` was refactored to be compliant with [RFC 0042](https://github.com/NixOS/rfcs/blob/master/rfcs/0042-config-option.md). To be precise, this means that the following things have changed:
 
diff --git a/nixos/modules/services/networking/dhcpcd.nix b/nixos/modules/services/networking/dhcpcd.nix
index 9a0b29fbe5a7..8b6d3fc55f3e 100644
--- a/nixos/modules/services/networking/dhcpcd.nix
+++ b/nixos/modules/services/networking/dhcpcd.nix
@@ -81,9 +81,12 @@ let
         noipv6
       ''}
 
-      ${cfg.extraConfig}
+      ${optionalString (config.networking.enableIPv6 && cfg.IPv6rs == null && staticIPv6Addresses != [ ]) noIPv6rs}
+      ${optionalString (config.networking.enableIPv6 && cfg.IPv6rs == false) ''
+        noipv6rs
+      ''}
 
-      ${optionalString config.networking.enableIPv6 noIPv6rs}
+      ${cfg.extraConfig}
     '';
 
   exitHook = pkgs.writeText "dhcpcd.exit-hook"
@@ -160,6 +163,16 @@ in
       '';
     };
 
+    networking.dhcpcd.IPv6rs = mkOption {
+      type = types.nullOr types.bool;
+      default = null;
+      description = lib.mdDoc ''
+        Force enable or disable solicitation and receipt of IPv6 Router Advertisements.
+        This is required, for example, when using a static unique local IPv6 address (ULA)
+        and global IPv6 address auto-configuration with SLAAC.
+      '';
+    };
+
     networking.dhcpcd.runHook = mkOption {
       type = types.lines;
       default = "";